Some people work internally with -p0-patches which has the danger thatone forgets to convert them to -p1 before mainlining. Bitten myself andseen p0-patches in mailing lists occasionally, this patch adds a warningto checkpatch.pl in case a patch is -p0. If you really want, you canfool this check to generate false positives, this is why it just spits awarning. Making the check 100% proof is trickier than it looks, so let'sstart with a version which catches the cases of real use.